FR2574654A1 - ORTHOPEDIC APPARATUS FOR EXTERNALLY FIXED BONE OR FRACTURE BONE PARTS WITH A WIDE RANGE OF ADAPTABILITY - Google Patents

Abstract

THE INVENTION CONCERNS AN ORTHOPEDIC APPARATUS FOR THE AXIAL EXTERNAL FIXATION OF BONE OR PARTS OF BONE FRACTURES, WITH A WIDE RANGE OF ADAPTABILITY. THIS APPARATUS CONSISTS OF A CENTRAL BODY 10 SHAPED WITH AT LEAST THREE PARTS 12, 13, 14 WHICH CAN MOVE ONE IN RELATION TO THE OTHER BY TELESCOPIC SLIDING, WITHOUT THE POSSIBILITY OF ROTATION ONE IN RELATION TO L '' OTHER, EQUIPPED WITH SEPARATE LOCKING MEANS 30, 32, 34, 36 WHICH CAN BE ACTIONED SELECTIVELY FOR EACH PAIR OF PARTS, WITH A CYLINDER MECHANISM 11 EQUIPPED WITH AT LEAST THREE ELEMENTS 40, 45, 50 WHICH CAN BE SCREWED ONE INTO THE OTHER AND MOVE ALONG A COMMON AXIS, UNDER THE EFFECT OF THE ROTATION OF ONE OF THE ELEMENTS, THE ELEMENTS LOCATED AT THE END OF THE CYLINDER BEING EQUIPPED WITH ANCHORS WHICH CAN BE HOUSED BY REMOVABLE WAY IN THE CAVITIES OF ECCENTRICS 21, 21 OF THE CENTRAL BODY.

Description

ORTHOPEDIC APPARATUS FOR AXIAL EXTERNAL BONE MOUNTING

  OR FRACTURE BONE PARTS WITH A WIDE RANGE OF ADAPTABILITY.

  The invention relates to an orthopedic appliance of the type described in U.S. No. 4,312,336, for the axial external fixation of bone or parts of fractured bone. The apparatus object of the aforementioned patent is composed of a

  central body consisting of two parts that can move the

  relative to each other by telescopic sliding, which can not rotate relative to each other, and at the ends of which nail holders are connected by means

  ball joints. This apparatus is provided with means permitting

  selectively blocking both parts of the central body to a desired length of that body. In addition, this device is also provided with cylinders to enlarge or reduce the length of the central body. This device is able to solve the problems inherent to long bones such as, for example, the tibia or the femur, in particular

  when the surgeon has a certain amount of

  those whose central bodies have different lon-

  minimum settings, which makes it possible to choose the device that re-

  best meets the requirements of the case. However, in the case of smaller bones such as the radius, the ulna or others, for which it is desired to have an apparatus of smaller size and where it is however desirable to obtain a larger ratio of variation of the length of the central body with the same apparatus, the apparatus according to

  patent proves unsuitable for use.

  The main object of the invention is therefore to provide an orthopedic device which, with a small footprint of the central body, is able to give a wide range

  adaptability of the length of the central body and in the-

  congestion and adaptability go far beyond

  beyond the possibilities of already known devices.

  According to the invention, the technical problem related to this objective has been solved by an orthopedic apparatus intended

  axial external fixation with a wide range of adapta-

  tability, comprising a central body of variable length at the ends of which two nail holders are assembled by means of ball joints whose centers of rotation lie on the longitudinal axis of the central body, means

  selectively operable associated respectively

  at both ball joints to lock the nail holders

  in a particular orientation, a cylinder mechanism can

  to be selectively actuated acting near the ends of the central body, characterized in that the central body is constituted by at least three parts which

  can move relative to each other by

  telescopic lifting by means of axial guide means

  ti-rotatory and blocking, which can be selectively

  between those parts, and two tubular pins

  eccentric rests mounted free in rotation in the parts

  mobile telescopic sliding extremities and which

  accommodate mounting holes for two dowels of one

cylinder mechanism.

  The apparatus according to the invention has the advantage of being

  to be able to solve several orthopedic problems for each of which, in the past, the surgeon had to

  first of all to choose an apparatus with a central body of a

  appropriate extensibility.

  Another particular advantage lies in the fact that the apparatus makes it possible to obtain an adaptability such that the maximum length of the central body is greater than twice the minimum length, which is entirely impossible.

with already known devices.

  An embodiment of the invention will now be described by way of nonlimiting example with reference to the accompanying drawings, in which: - Figure 1 is a side elevational view, of which

  some parts are eliminated and other parts

  cut to show the interior details; FIG. 2 is a view of the apparatus, similar to

  that of Figure 1 but on which the apparatus is

  born 90 relative to the arrangement of Figure 1 and with portions in section along the plane 2-2 of Figure 1; FIG. 3 is an exploded view of the parts of the central body of the apparatus of FIGS. 1 and 2; Figure 3A is an enlarged partial longitudinal section of a stop screw provided for locking two mobile parts by telescopic sliding of the apparatus of Figures 1 and 2; FIG. 4 is a side elevational view of a jack mechanism used with the apparatus of FIGS. 1 and 2, in the maximum extension position;

  FIG. 5 is a view of the central body of the

  3, in the maximum contraction position - FIG. 6 is a view of the actuator mechanism of FIG.

  Figure 4 in the maximum contraction position.

  In Figures 1 and 2, the apparatus is shown in

  its position of adaptation of intermediate length, in the-

  which parts of the central body 10 which are movable by telescopic sliding and the three parts of the cylinder 11 are partially visible. The central body parts are cylindrical and comprise an inner part 12,

  an intermediate portion 13, or sleeve, and an outer portion

  14, which has a cylindrical cavity capable of

  to receive the parts 12 and 13 fully fitted with

  lescopiquement. Two nail holders 17, 15 are connected to the ex-

  tremities of the body 10 by rotary joints 18, 16 may

to be selectively blocked.

  The setting of the locking of the ball joint 18, which can be loosened quickly, is made possible by the head to

  hexagon socket 20 of a tubular pin 21 with an internal cavity

  cylindrical sleeve which extends perpendicular to the longitudinal axis of the body 10, along an axis 22, and which is rotatably mounted in the head 19 of the inner portion 12. Between

  spaced spans, pin 21 forms an eccentric cy-

  lindrique 23 by means of which the bowl 24 of the seal can be pressed against the ball 18. The releasable locking of the other ball joint 16 is of a similar construction;

  indeed, it comprises a tubular pin 21 'which can turn

  around the axis 22 'and housed in the closed end of

  the outer portion 14 of the central body.

  Each nail carrier 15, 17 is shown with two nails 25 and, when the locking of the pin 21 (21 ') is loosened, the corresponding nail holder is entirely free to take the desired orientations, by rotation around the center of the ball, which is on the longitudinal axis of the central body, or it can be separated from the body 10 by a partial rotation of the shell 26 (26 ') mounted on the corresponding end of the body 10 by a bayonet assembly . Further details relating to the nails, the nail holders and the locking and unlocking mechanism are contained in the aforementioned 4,312,336 patent. The pins 22-22 'of the pins are

  parallel to each other thanks to an anti-rotation key

  between Parts 12, 13 and 14, as well as this

clearly shown in Figure 3.

  In the case of part 12, a groove with a flat bottom 30,

  relatively wide and shallow, is provided in a

  plate 31 of the cylindrical outer surface. This groove is

  tends to be slightly shorter than

axial of the cylindrical surface.

  In the case of the sleeve 13, a stop screw 32 placed radially close to the end of the part 12 which

  is close to the head 19, ends at a cylindrical tip

  that flat 33 having a diameter D serving as a guide

  be the walls of the groove 30; the flat face of the tip 33 is pressed against the bottom of the groove to stably fix the position of the sleeve 13 along the length of the portion 12. When the screw 32 is loosened, the tip 33 acts as an anti-lock key -rotatory, thus facilitating the telescopic displacements between the limits of the length

groove 30.

  The sleeve 13 further has an integral groove 34

  similar to groove 30, see Figure 2, which is

  see in the flat 35 and is of length equal to that of the

sleeve 13.

  The open cylindrical end of the outer portion 14 of the central body houses the head of a stop screw 36, which

  may be identical to screw 32, and which is intended to co-

  radially with the groove 34. As long as the tip of the screw 36 remains in the groove 34, there is an anti-rotary connection by keying between the parts 13 and 14,

  whose telescopic movements are limited to

  Figure 34. At one end of the central body portion 14 there is provided an opening 37 which allows access to the head of the screw 32, even when the central body is in the maximum telescopic contraction position.

(Figure 5).

  The body parts 10, nail holders and ball joints associated with this body can be locked in determined length or inclination relationships, so it is obvious that when the desired relationships have been selected, they can be fix using a single tool (for example an Allen key), both to screw the screws 32, 36 to refusal and to block the ball joints by means of

eccentric pins 21, 21 '.

  For the precision of the movements of the parts of the body, it is preferable that the actuator mechanism 31 can be removably mounted on the parts 12 and 14 of the

  central body. The cylinder mechanism ll is also essential.

  actually formed of three elements that can slide relative to each other along a common axis, such as

  shown in Figures 1, 2, 4, 6.

  As can be seen in Figure 4, an ex-

  40 is threaded externally over most of

  of its length. At one end, it is constructed so

  re to be retained and rotatable in a hub 41 which carries a radial pin 42; the end 43

  the element 40 emerges from the hub 41 and is of a configuration

  with hexagon socket to be able to receive a male key, preferably the same as that used for the screws 32

  and 36. At the other end, the element 40 is provided with a small

  tite circular flange 44, projecting outwards,

  serving as a guide in the internal bore of the element

  intermediate 45, or sleeve. The lower end of the

  element 45 is characterized by a small flange 46, directed radially inwards, which is screwed on the thread of the element 40; the maximum extension limit of this coupling is reached when the flange 44 comes into abutment stop against the flange 46, while reaching the limit of maximum contraction when the collar 47, close to the hub 41, abuts against the collar

46.

  The sleeve 45 is threaded externally, except over the length of a small collar 48 directed radially outwardly, which constitutes a guide inside the bore of an outer element 50. The lower end of the element 50 has a small flange 51 directed radially inwards and which is screwed on the thread

  the element 45; the limit of maximum extension of this

  coupling is reached when the flange 48 abuts against the collar 51 while reaching the limit

  maximum contraction when the closed end of the

  50 abuts against the collar 48, slightly

below the ankle 52.

  The activation of the jack mechanism 11 is performed by simply turning the element 40, by means of a male key

  inserted into the hexagon socket of the extremity

  43. The threads threaded into each other,

  in 40-46 and 45-51, are preferably identical.

  If one begins to act on the jack mechanism in the position of Figure 6, the assembly 45-51 can be the

  first to set in motion and can continue his

  until the flange 51 stops against the

  flange 48 before the twisting action sets in motion

  coupling 46-40; this advance ends when the collar 46 abuts against the collar 44, so that the maximum extension state designated in FIG. 4 is obtained

by "S max".

  To return the cylinder mechanism Il to the maximum contraction position, indicated in FIG. 6 by "S min", it suffices to rotate the element 40 in the opposite direction

  of the one used to get the maximum extension.

  Naturally, the plugs 42, 52 are dimensioned so as to be selectively inserted into the pin holes 21, 21 '. It should be noted that in the example described, the maximum extension length is greater than twice the length of maximum contraction but it is obvious that one can further increase this ratio of length by realizing the central body and the cylinder in four parts or

more than four parts each.

  It is evident from the above that, due to its particular structure, the orthopedic device described above can be used to solve a wide range of problems.

  range of situations that could only have been solved

  through the use of apparatus conforming to the

  United States vet 4,312,336, devices that differ from one another

  others by the dimensions of their central bodies.

  In addition, the wide range of adaptability of the length

  of the central body according to the invention entails no modification

  pre-selected angular positions of the nail holders, and the arrangement allows easy access

  to the screws 32, 36, due to their offset locations

  gularly with respect to the plane which contains the axes 22,

22 'eccentric pins.

  With the apparatus according to the invention, it is also possible to vary the orientations of the nail holders

  while maintaining the length of the central body unchanged.

  It is further obvious that modifications may be made by those skilled in the art to the object of the invention in its practical use without departing from the field of

  the invention which is defined by the appended claims.

Claims (5)

R E V E N D I C A T I ONS   1 - Orthopedic apparatus for external fixation   non-axial arrangement of fractured bone or fractured bone parts having a wide adaptability range, comprising a central body (10) of variable length at the ends of which two nail holders (15, 17) are assembled by means of ball joints. (16, 18) whose centers of rotation lie on the longitudinal axis of the   central body, means that can be selectively   respectively associated with the two ball joints (16,   18) for locking the nail holders (15, 17) in an orientation   determined, a cylinder mechanism (11) that can be   selectively acting near the ends of the central body (10), characterized in that the central body (10) is constituted by at least three parts (12, 13, 14) which can move relative to one another by telescopic sliding, by means (30, 32, 34, 36) of anti-rotational and locking axial guidance, which can be actuated selectively between said parts and by   two eccentric tubular pins (21, 21 ') mounted   rotating in the end portions (12, 14) and constituting mounting housings for two pegs (42, 52) of a jack mechanism.   2 - Apparatus according to claim 1, characterized by   the fact that the part (13) is constituted by a cymbal sleeve   lindrical, intermediate, concentric to the longitudinal axis   of the body (10) radially interposed between the parts   (12) and outer (14) and mounted to slide   lescopique with respect to these parts, the outside part   (14) being provided with an open slot (37).   3 - Apparatus according to claim 1, characterized in   what the means of anti-rotational axial guidance and blocking   cage acting between the parts of the central body (10) are   consisting of two stop screws (32, 36) with a cylindrical point   than flat (33) that can be screwed radially into the man-   chon (13) and in the outer portion (14), and which are angularly offset relative to one another as well as   relative to the plane containing the axes (22, 22 ') of the bro-   ches (21, 21 '), and by two grooves (30, 34) having a flat bottom and side walls and which are of a length   little less than that of the flats (31, 35) of the   (12) and the sleeve (13) on which they are formed.   These grooves cooperate with the tips (33). 4 - Apparatus according to claim 3, characterized in that the screws (32, 36) have a hexagon head. - Apparatus according to claim 1, characterized in that the tubular pins (21, 21 ') are hexagonal hollow at one of their ends.   6 - Apparatus according to claim 1, characterized in that the cylinder mechanism (11) is constituted by   least three cylindrical elements (40, 45, 50) arranged   centrally along a common axis of movement, the   elements (40, 45) each having an internal bore   cylindrical and ending at one end by a collar   threaded flange (46, 513 directed radially inwards,   which is screwed on the external thread of the corresponding element.   the elements (40, 45) terminating in a radially outwardly directed flange (44, 48) contained in the corresponding cylindrical bore of another element (45, 50) and all the threads having the same pitch and developing in the same direction.   7 - Apparatus according to claim 6, characterized by   the fact that at its end which is the opposite of the glue-   rette (51), the element (50) carries a peg (52), inserted   in this element and which protrudes radially towards the former   interior, and in that, opposite the flange (44), the element (40) is provided with a collar (47) below which this element terminates at one end (43) at six hollow portion which is rotatably connected to a hub (41) by means of a pin (42) projecting radially towards the outside on the hub (41).